Combined piston and packing-king



J. T. WILSON.

COMBINED PISTON AND PACKING RING.

APPLICATION FILED APR- 71 1919.

1,380,454, Patented June 7, 192 1.

/'7Ci /a/e c A TTORNE Y.

UNITED STATES PATENT OFFICE. f

JOHN '1. WILSON, OF ALAMEDA, CALIFORNIA.

COMBINED PISTON AND PACKING-BIN G.

Specification of Letters Patent. Patented June '7, 1921.

Application filed April 7, 1919. Serial No. 288,040.

same.

A gas engine piston usually consists of an integral cylindrical casting provided with circumferential grooves in its exterior surface to receive packing ringswhich frictionally bear against the interior surface of the cylinder to form tight joints therewith during all periods of the reciprocating motions of the piston. The front end of the piston and the packing rings which project slightly beyond the exterior surface of the piston are subjected to great pressure by the generated energy of the explosive charge. The packing rings necessarily are of small cross sectional area and cut apart so they can be sprung over the end of the piston into the grooves. Being of small dimensions, they soon wear out and the piston body then frictionally engages the interior surface of the cylinder and wears away the metal of the cylinder and opens a passageway for the gases generated by the explosion. Also the ends of the rings frequently break and become displaced so the gases can pass. Under the same conditions when explosive charges are drawn into the explosion chamber, a vacuum being formed therein, lubricating oil from the crank chamber is sucked past the pack ing rings into the explosion chamber, where it becomes carbonized and fouls the cylinder and piston.

These conditions obviously impair the efficiency of the engine, and the remedy therefor does not consist simply in using wider packing rings, for the wider the ring, the greater the pressure beneath it and the greater the friction between the ring and the cylinder. 4

The object of the present invention is to cure these imperfections by providing a packing ring, of a shape conforming to the shape of the groove in the piston, and presenting a relatively large area ofexterior Wearing surface and a much less area of surface at the-interior to be acted upon by the pressure of the explosive gases and the pressure of the explosive charge when being compressed-that is, to exclude from part of the interior surface of the ring the pressure due to the compression of the charge and also the explosion of the charge; but when the charge is drawn in by suction, a vacuum being formed in the explosion chamber, permitting air at atmospheric pressure containing more or less of lubricating oil, it passes beneath the entire under surface of the packing.

The invention consists in a single cut resilient expansible packing ring and a piston having agroove of a shape in conformity with the shape of the ring whereby the results above set forth are attained. f

Further, the invention consists incertain novelties of construction and-relative arrangements, as herein set forth, of the ring,

example of the embodiment of the invention constructed and the-parts combined according to the best' of'the several modes of procedure I have'so far devised for the attainment of the ends set forth.

Figure l is avertical sectionin elevation of a gas engine piston and cylinder showing my invention, several packing rings being shown in section.

Fig. 2 shows the face of a ring adjacent the explosion pressure end of the piston.

Fig. 3 is the opposite face view of Fig. 2*. r Fig. 4 is a top plan view of Fig. 2. Fig. 5 is an enlarged view ofthe joint member in perspective. Fig. 6 illustrates the position of the packing ring in the groove whenthe charge is being drawn into the explosion chamber.

Fig. 7 illustrates the position of the ring when the charge is being compressed and also when the explosion is taking place in shape of the grooves in its exterior surface.

The lines B-B and shading lines represent part of the interior circular surface of'the engine cylinder 'presenting a smooth surface throughoutyandpart of the metal of the cylinder. G is the nd of the piston forming the movable inclosing boundary of the explosion chamber D, and E is the end of the piston facing the inclosed crank chamber space F which contains a heavy lubricating oil or other lubricant. G designates the grooves in the exterior surface of the metallic body of the piston. it are the packing rings.

Referring to single combined glOO'fQ and ring, it will be noted that each is adapted to the shape of the other. The outer part of the groove 1 is of the same width throughout the circumference of the piston. its depth at 2 adjacent the end of the piston next to the explosion chamber is greater than its depth at 3 adjacent the crank chamber end of the piston. In other words, the groove is of a general ln-shape and the vertical surfaces defining the same are plain to match the surfaces at the sides of the packing ring.

The ring R is shaped to loosely fit the groove, its exterior portion being wider than its interior portion, and. of general l.-shape in cross section. The part l may be called a flange and in the groove it is remote from the explosion chamber and faces the crank chamber. The ring may project slightly from the groove to engage the interior surface of the cylinder and there should be a slight space as indicated between the side and bottom surfaces and the metal surfaces defining the groove so the ring can float longitudinally relative to the axis of the piston and also at right angles thereto so as to frictionally engage the interior surface of the cylinder throughout.

The ring is in a single piece, except the joint plate, and of resilient expansible metal. It is cut or severed so it can be sprung over the end of the piston. A tight joint must be provided at the out ends of the ring and in this instance it is formed as shown by the drawing.

Tongues 5, 5 are fashioned at the ends of the ring, and a oint member or piece fashioned to match them and the ends of the ring. The joint member has two recesses 6, 6 which may merge into a single slot to re ceive the tongues. a flange 7, and a bottom plate 8. The parts of the ring to exclude explosion pressure to and beneath the g d. part of the ring are the bottom plate 8 and the part of the joint member design ated by 9 fitting the vertical surface of the ring on the side thereof adjacent the explosion pressure end of the piston and the explosion chamber.

It should be noted here that in gas engine practice, unlike that when steam is the motive power, the packing ring must loosely fit the groove in the piston so that when the ring and groove become fouled by the products of incomplete combustion of the charge, which is always the case more or less, the ring will not stick in the groove. That is,

-1l'8 under sun. not excessively force the ring against the inte ior surface of the cylinder, but sufto prevent the passage of oil beyond the explosion chamber. The

cssure the ring i. friction and wear of the ring, so a wide ring may be employed under these conditions. The ring occupies the position shown in Fig. 6, the surfaces of the ring and groove at o;

b-einr in frictional contact so as to form a W 1 against the passage of air or oil. .ticcondly, when the charge is being compressed the ring shifts to the position shown the mixture under compression A s o the space 7) beneath only part of the under suri'ace of the rin the surfaces a n n the ring and groove at c forming a tight so the pressure cannot reach the under dly, when the explosion of the charge place the ring under very great iressure maintains its position shown in Fig. 7 and excludes pressure from the under surc the flange of the ring.

Under the last two conditions enumerate-d th pressure under part of the ring is sufficient to force the ring into frictional contact w' h the interior surface ofthe cylinmaintain a tight joint therewith so a much wider ring can be used without occasioning; excessive wear thereof or wear of th interior surface of the cylinder.

It is clear that a piston and ring combined and operating as herein described attain very desirable results. A relatively large bearing surface is secured so the ring will wear much longer than a narrower ring which. is liable to break, and the ring is not forced against "he interior surfaceof the surface of the ring. .t is also clear that oil tom the crank chamber cannot pass the when a vacuum is caused in the explosion chamber for drawing in the explosive charge.

What I claim is:

The combination with a cylinder and a piston having a circumferential groove wider adjacent the exterior surface of the piston. than at the bottom. the greatest depth atmospheric pressure, at 15 of said groove being adjacent the explosion surface of the ring While the explosive chamber, of a single cut resilient expansible charge is being drawn into the explosion flanged packing rlng of a shape in cross secchamber, said groove in the piston When the tion matching and loosely fitting the groove packing ring is in place being entirely closed 5 and its entire exterior surface frictionally as far as possible to the entrance of gas 15 engaging the interior surface of the cylinunder pressure to the space beneath the der, and a joint member excluding explosion packing ring.

and charge compression pressure from the In testimony whereof I affix my signature. flanged portion of the ring, but admitting 10 atmospheric pressure to the entire under JOHN T. WILSON. 

